The extensive intergenerational molecular effects of ocean acidification on the olfactory epithelium transcriptome of a marine fish are associated with a better viral resistance

Background Progressive climate-induced ocean acidification (OA) impacts marine life in ways that are difficult to predict but are likely to become exacerbated over generations. Although marine fishes can balance internal acid-base homeostasis efficiently, indirect ionic regulation effects that alter neurosensory systems can result in behavioural abnormalities. In marine invertebrates, OA can also affect immune system function, but whether this is the case in marine fishes of ecological and commercial importance is not yet understood. Farmed fish are highly susceptible to disease outbreak yet strategies for overcoming such threats in the wake of OA are wanting. Here, we exposed two generations of the European sea bass (Dicentrarchus labrax) to end-of-century predicted CO2 levels (IPCC RCP8.5), with parents being exposed for four years and their offspring for two years. Our design included a transcriptomic analysis of the olfactory rosette (collected from the F1 offspring) and a viral challenge (exposing F1 offspring to betanodavirus) where we assessed survival rates. Results We discovered long-term intergenerational molecular trade-offs in both sensory and immune systems. Specifically, RNA-Seq analysis of the olfactory rosette, the peripheral olfactory organ, from two-year-old F1 offspring revealed extensive regulation in genes involved in ion transport and neuronal signalling, including GABAergic signalling. We also detected extensive OA-induced intergenerational up-regulation of genes associated with odour transduction, synaptic plasticity, neuron excitability and wiring and down-regulation of genes involved in energy metabolism. In addition, intergenerational exposure to OA induced up-regulation of genes involved in innate antiviral immunity (pathogen recognition receptors and interferon-stimulated genes) in combination with down-regulation of the protein biosynthetic machinery. Consistently, OA-exposed F1 fish challenged with betanodavirus, which causes damage to the nervous system of marine fish, had acquired improved resistance. Conclusion F1 exposed to OA-intergenerational acclimation showed superior viral resistance, though as their metabolic and odour transduction programs were altered, odour-mediated behaviours might be consequently altered. Our results reveal that trade-offs in adaptive plastic responses is a core feature of the olfactory epithelium transcriptome in OA-exposed fish, suggesting that intergenerational plasticity propagate with progressive exposure to OA and will have important consequences for how cultured and wild fish interacts with its environment.

Proximate and antinutritional assessments of stingrays

Stingrays are one of the marine fishes that inhabit the shallow part of the ocean. They are well known to the locals as cuisine and its parts as accessories for items such as handbags, belts, and decorations. Stingrays of species Himantura undulata and Maculabatis gerrardi are commonly caught by fishermen of Sarawak, but most of its nutritional and antinutritional factors both species are unknown. This study focused on the analysis of some proximate composition such as moisture, ash, and lipid content. Analysis of total organic matter was done as well. The stingrays were obtained from local fish market in Kuching, Sarawak. The method used for moisture (wet basis), ash, and total organic matter is of AOAC (method 930.15), while crude lipid content was based on the Chedoloh method of extraction. The study revealed that H. undulata and M. gerrardi are nutritious in terms of moisture, ash, and lipid content to be 78.44 and 80.74% (dry basis), 0.48 and 1.37%, 2.46 and 7.74% respectively.

Fish diversity drives regional productivity but not stability in southeastern United States coastal marine fishes

Aim: Ecosystem-based management requires accurate predictions on how biotic and environmental factors interact to deliver ecosystem services. Biodiversity-ecosystem function (BEF) theory predicts that as diversity increases, the ecosystem will become more productive (positive diversity-productivity relationship: DPR) and more stable (positive diversity-stability relationship: DSR). Support for BEF has been primarily derived from fine-grained, non-harvested systems. The purpose of this study is to examine the robustness of BEF predictions for the DPR and DSR by examining how well fish diversity predicts productivity and stability of fish, shrimp, and flounder at a regional scale. Location: Southeast coast of United States. Time Period: 1989 - 2015. Major Taxa Studied: Marine Fishes. Methods: We used 27 years of the SEAMAP-SA Coastal Trawl Survey database to derive estimates of fish, shrimp, and flounder biomass (i.e., productivity), temporal stability of biomass (i.e., invariability of productivity), and fish community species richness. We pooled trawls into 22 km x 22 km raster cells and 3-year time bins. We controlled for variation in sampling effort using sample-based rarefaction. We compared the ability of fish species richness, water salinity, and water temperature to predict biomass and stability of all fish, shrimp, and flounder using multiple linear regression. Results: Both the DPR and DSR exhibited positive log-log linear trends as expected, but the DPR had a much stronger signal. Species richness outperformed the environmental covariates in both the fish and shrimp DPR models. Surface temperature was the most important variable in both flounder models. Overall, our models better explained productivity than stability. Main Conclusions: The DPR and DSR are relevant at regional scales in a commercially important fishery although support for the DSR is less justified than DPR. Further investigation into the underlying mechanisms driving the DPR and DSR are necessary to design management around BEF theory.